Ultrastructural properties of bone mineral of control and tiludronate-treated osteoporotic rat

Bisphosphonates have been widely used in the treatment of human bone pathol ogies including osteoporosis. In this case, bisphosphonates have been shown to reduce bone resorption, thereby increasing the mass and mechanical resi stance of bone. Determining the effects of these molecules on the propertie s of the bone apatite crystals could provide a better insight into the mech anism of bisphosphonate/bone interaction. The aim of this study was to dete rmine the ultrastructural effects of a third generation bisphosphonate (til udronate) on the morphology, size, distribution, chemical composition, and structure of apatite crystals in bone (trabecular) in a rat osteoporotic mo del. Four groups of rats were studied: (1) sham operated, (2) untreated ova riectomized (OVX), (3) OVX rats which received 35 mg/kg of tiludronate, (4) OVX rats which received 160 mg/kg of tiludronate. The rats of groups 3 and 4 received tiludronate orally in 2 consecutive days every week for I year. Scanning electron microscopy (SEM), high and low resolution transmission e lectron microscopy (TEM), and electron microprobe analysis (EDX) were used for the ultrastructural characterization of the bone mineral. This study de monstrated that tiludronate slightly increased the width of bone apatite cr ystals without changing any other crystal characteristics.